Conventionally, a refuse incineration facility for incinerating urban refuse for disposal is provided with a fire-grate-type refuse incinerator. Sometimes there is provided a fluid bed incinerator. In addition, an ash fusion furnace is often installed for reducing the volume of incineration ash discharged from the refuse incinerator and for rendering it harmless.
Recent urban refuse is characterized by an increase in the volume of plastics contained in the refuse and an increase in the amount of refuse as a whole.
The fire-grate-type refuse incinerator is very effective because refuse, other than bulky refuse, can be fed into the incinerator as is without being comminuted. However, when refuse containing plastics in an amount of 30% by weight or more is incinerated, there is the possibility that molten plastics will flow down under the fire grate to damage it or to cause a fire accident. Thus, the firegrate-type refuse incinerator has a problem in that it cannot accommodate refuse containing a large amount of plastics. Furthermore, incinerators must be made larger to accommodate increasing amounts of refuse. In a flat bed combustion system, combustion takes place on the surface of a fire grate. The fire grate may be damaged if it is required to support too large a load. Thus, the volume of refuse which can be incinerated in a typical refuse incinerator is said to be limited to 1000 tons per day.
On the other hand, the fluid bed incinerator is suitable for incineration of refuse containing a large amount of plastics because material to be incinerated is incinerated through suspended combustion while the material is caused to float and flow in a fluid layer. However, since the fluid be incinerator requires much power for breaking and fluidizing refuse, the volume to be incinerated in generally limited to 200 tons as day, and it is difficult to increase the volume.